// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/barrier_closure.h"

#include "base/bind.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace {

void Increment(int* count) { (*count)++; }

TEST(BarrierClosureTest, RunImmediatelyForZeroClosures)
{
    int count = 0;
    base::Closure done_closure(base::Bind(&Increment, base::Unretained(&count)));

    base::Closure barrier_closure = base::BarrierClosure(0, done_closure);
    EXPECT_EQ(1, count);
}

TEST(BarrierClosureTest, RunAfterNumClosures)
{
    int count = 0;
    base::Closure done_closure(base::Bind(&Increment, base::Unretained(&count)));

    base::Closure barrier_closure = base::BarrierClosure(2, done_closure);
    EXPECT_EQ(0, count);

    barrier_closure.Run();
    EXPECT_EQ(0, count);

    barrier_closure.Run();
    EXPECT_EQ(1, count);
}

class DestructionIndicator {
public:
    // Sets |*destructed| to true in destructor.
    DestructionIndicator(bool* destructed)
        : destructed_(destructed)
    {
        *destructed_ = false;
    }

    ~DestructionIndicator() { *destructed_ = true; }

    void DoNothing() { }

private:
    bool* destructed_;
};

TEST(BarrierClosureTest, ReleasesDoneClosureWhenDone)
{
    bool done_destructed = false;
    base::Closure barrier_closure = base::BarrierClosure(
        1, base::Bind(&DestructionIndicator::DoNothing, base::Owned(new DestructionIndicator(&done_destructed))));
    EXPECT_FALSE(done_destructed);
    barrier_closure.Run();
    EXPECT_TRUE(done_destructed);
}

void ResetBarrierClosure(base::Closure* closure)
{
    *closure = base::Closure();
}

// Tests a case when |done_closure| resets a |barrier_closure|.
// |barrier_closure| is a Closure holding the |done_closure|. |done_closure|
// holds a pointer back to the |barrier_closure|. When |barrier_closure| is
// Run() it calls ResetBarrierClosure() which erases the |barrier_closure| while
// still inside of its Run(). The Run() implementation (in base::BarrierClosure)
// must not try use itself after executing ResetBarrierClosure() or this test
// would crash inside Run().
TEST(BarrierClosureTest, KeepingClosureAliveUntilDone)
{
    base::Closure barrier_closure;
    base::Closure done_closure = base::Bind(ResetBarrierClosure, &barrier_closure);
    barrier_closure = base::BarrierClosure(1, done_closure);
    barrier_closure.Run();
}

} // namespace
